Method for manufacturing silicon-containing thin film

ABSTRACT

The present invention relates to a method for forming a silicon-containing thin film using a chlorosilane compound represented by Si n Cl 2n+2  (wherein, n is an integer of from about 3 to about 10), and a high-quality silicon nitride thin film can be formed to a uniform thickness on a surface including a protrusion or recess having a high aspect ratio by an atomic layer deposition method using an ammonia gas at a low temperature of particularly about 560° C. or less.

TECHNICAL FIELD

The invention relates to a method for forming a silicon-containing thinfilm using a chlorosilane compound represented by Si_(n)Cl_(2n+2)(wherein, n is an integer of from about 3 to about 10).

BACKGROUND

A silicon nitride thin film has been used for various purposes inmanufacturing a semiconductor device. In recent years, with continuouslyminiaturizing semiconductor devices, a silicon nitride thin film of 30nm or less, or even 10 nm or less has been needed. By way of example,Korean Patent Laid-open Publication No. 10-2011-0102686 (InternationalPatent Application Publication No. WO2010/025024) discloses that adielectric material such as silicon nitride is preferable as a linermaterial of an isolation trench and that a thickness thereof is from 20Å to 100 Å, i.e., 2 nm to 10 nm. Further, U.S. Patent Laid-openPublication No. 2012/0085733 discloses that when an uneven surface iscovered with a spacer layer having a uniform thickness in order toincrease a pattern density after a lithography process, silicon nitridecan be used as a material of the spacer layer. In order to form apattern having a half-pitch of 15 nm for manufacturing a semiconductordevice, a nitride spacer needs to be formed to have a thickness of about15 nm on the uneven surface [Chen Y, Xu P, Miao L, et al.; “Self-alignedtriple patterning for continuous is scaling to half-pitch 15 nm” SPIEAdvanced Lithography. 0001; 79731P-8. doi: 10.1117/12.881645].

U.S. Pat. No. 8,143,131 discloses a method in which a silicon oxidespacer is formed on a gate stack of a transistor and then a siliconnitride spacer is formed to have a thickness of 20 Å to 200 Å, i.e., 2nm to 20 nm, on the silicon oxide spacer. The atomic layer depositionmethod in which gaseous materials for forming films are alternatelybrought into contact with a substrate surface is particularlyadvantageous in forming a film having a uniform thickness on a surfaceincluding a trench having a small width and a high aspect ratio. Athickness of the spacer formed on the gate stack needs to be preciselycontrolled. Instead of the conventional low pressure chemical vapordeposition method, the atomic layer deposition method for forming asilicon nitride thin film at a low temperature has been actively studied[Raaijmakers I; “Current and Future Applications of ALD inMicro-electronics” ECS Transactions, Volume 41, Issue 2, pp 3-17 (2011).doi: 10.1149/1.3633649].

However, in spite of such a need, there has not been known a method forforming a silicon nitride thin film having excellent properties to auniform thickness on a surface including a trench having a small widthand a high aspect ratio by the atomic layer deposition (ALD) method at atemperature of 560° C. or less, 520° C. or less, 500° C. or less, or450° C. or less.

DETAILED DESCRIPTION OF THE INVENTION Problems to be Solved by theInvention

In view of the foregoing problems, one purpose of the present disclosureis to provide a method for forming a silicon-containing thin film to auniform thickness on a surface of a substrate including a protrusion orrecess such as a fine trench.

Another purpose of the present disclosure is also to provide a methodfor forming a silicon oxide thin film, a silicon nitride thin film, or asilicon carbonitride thin film to a uniform thickness of about 100 nm orless on a surface of a substrate including a protrusion or recess.

Yet another purpose of the present disclosure is to provide a method forforming a silicon oxide thin film, a silicon nitride thin film, or asilicon carbonitride thin film to a uniform thickness on a surface of asubstrate including a protrusion or recess at a temperature of about800° C. or less.

Still another purpose of the present disclosure is to provide a methodfor forming a silicon oxide thin film, a silicon nitride thin film, or asilicon carbonitride thin film to a uniform thickness on a surface of asubstrate including a protrusion or recess at a low temperature of about560° C. or less, about 520° C. or less, about 500° C. or less, or about450° C. or less.

However, problems to be solved by the example embodiments of the presentdisclosure are not limited to the above-described problems. Although notdescribed herein, other problems to be solved by the present disclosurecan be clearly understood by those skilled in the art from the followingdescriptions.

Means for Solving the Problems

In a first aspect of the present disclosure, there is provided a methodfor forming a silicon-containing thin film, including: bringing a gasincluding a chlorosilane compound represented by the chemical formula ofSi_(n)Cl_(2n+2) (wherein, n is an integer of from about 3 to about 10)and a reactant gas including an element selected from the groupconsisting of nitrogen, oxygen, carbon, and their combinations intocontact with a substrate including at least one trench having an aspectratio of about 1 or more and a width of about 1 μm or less.

Effect of the Invention

In accordance with the present disclosure, it is possible to formvarious silicon-containing thin films each having a uniform thickness ona surface of a substrate including a protrusion or recess such a finetrench.

In accordance with an example embodiment of the present disclosure, itis possible to form a silicon oxide thin film, a silicon nitride thinfilm, or a silicon carbonitride thin film with a uniform thickness ofabout 100 nm or less on a surface of a substrate including a protrusionor recess.

In accordance with an example embodiment of the present disclosure, itis possible to form various silicon-containing thin films such as asilicon oxide thin film, a silicon nitride thin film, or a siliconcarbonitride thin film with a uniform thickness on a surface of asubstrate including a protrusion or recess at a temperature of about800° C. or less.

In accordance with an example embodiment of the present disclosure,there is provided a method for forming various silicon-containing thinfilms such as a silicon oxide thin film, a silicon nitride thin film, ora silicon carbonitride thin film with a uniform thickness on a surfaceof a substrate including a protrusion or recess at a low temperature ofabout 560° C. or less, about 520° C. or less, about 500° C. or less, orabout 450° C. or less.

In accordance with an example embodiment of the present disclosure, itis possible to form various silicon-containing thin films such as asilicon oxide thin film, a silicon nitride thin film, or a siliconcarbonitride thin film with a uniform thickness of about 100 nm or lessby the chemical vapor deposition (CVD) method or atomic layer deposition(ALD) method.

In accordance with an example embodiment of the present disclosure, itis possible to form various silicon-containing thin films such as asilicon oxide thin film, a silicon nitride thin film, or a siliconcarbonitride thin film with a uniform thickness of about 100 nm or lessby the ALD method.

The various silicon-containing thin films formed in accordance with thepresent disclosure may be used as a gate spacer, an isolation trenchliner, a spacer for increasing a pattern density after a lithographyprocess, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A and FIG. 1B are graphs each showing film growth according to anatomic layer deposition method in which a silicon substrate ismaintained at 520° C. and an exposure amount of the octachlorotrisilane(OCT) gas and an exposure amount of the ammonia gas independently varieswithin one cycle of the atomic layer deposition.

FIG. 2 is a graph showing film growth of silicon nitride thin filmsrespectively formed at various temperatures of a substrate using variouschlorosilane gases in accordance with Example 1, and Example 2 of thepresent disclosure, and Comparative Example 1.

FIG. 3A and FIG. 3B are graphs showing results of thicknesses andrefractive indexes of silicon nitride thin films respectively formed atvarious temperatures of a substrate in accordance with Example 1 of thepresent disclosure, the thickness and refractive indexes were measuredat right after the film formation, 1 day, 3 days and 6 days after thefilm formation.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings so that the presentdisclosure may be readily implemented by those skilled in the art.However, it is to be noted that the present disclosure is not limited tothe embodiments but can be embodied in various other ways. In drawings,parts irrelevant to the description are omitted for the simplicity ofexplanation, and like reference numerals denote like parts through thewhole document of the present disclosure.

Through the whole document of the present disclosure, the term“connected to” or “coupled to” that is used to designate a connection orcoupling of one element to another element includes both a case that anelement is “directly connected or coupled to” another element and a casethat an element is “electronically connected or coupled to” anotherelement via still another element.

Through the whole document of the present disclosure, the term “on” thatis used to designate a position of one element with respect to anotherelement includes both a case that the one element is adjacent to theanother element and a case that any other element exists between thesetwo elements.

Through the whole document of the present disclosure, the term“comprises or includes” and/or “comprising or including” used in thedocument means that one or more other components, steps, operationand/or existence or addition of elements are not excluded in addition tothe described components, steps, operation and/or elements unlesscontext dictates otherwise. The term “about or approximately” or“substantially” is intended to have meanings close to numerical valuesor ranges specified with an allowable error and intended to preventaccurate or absolute numerical values disclosed for understanding of thepresent disclosure from being illegally or unfairly used by anyunconscionable third party. Through the whole document, the term “stepof” does not mean “step for”.

Through the whole document of the present disclosure, the term“combinations of” included in Markush type description means mixture orcombination of one or more components, steps, operations and/or elementsselected from a group consisting of components, steps, operation and/orelements described in Markush type and thereby means that the disclosureincludes one or more components, steps, operations and/or elementsselected from the Markush group.

Through the whole document, a phrase in the form “A and/or B” means “Aor B, or A and B”.

Through the whole document, the term “silicon-containing thin film”refers to a thin film formed by containing silicon and at least oneelement selected from the group consisting of oxygen, nitrogen, andcarbon, and may further contain metal elements typically used in thesemiconductor field for forming composite thin films of silicon andother metal elements in addition to the silicon as necessary. By way ofexample, the silicon-containing thin film may include a silicon oxidethin film, a silicon nitride thin film, or a silicon carbonitride thinfilm, but may not be limited thereto.

Through the whole document, the term “reactant gas”, “additionalreactant gas”, or “second reactant gas” refers to a reactant gas used inaddition to a chlorosilane compound-containing reactant gas and may be agas including, for example, but not limited to, an element selected fromthe group consisting of nitrogen, oxygen, carbon, and theircombinations.

Hereinafter, a method for forming a silicon-containing thin film of thepresent disclosure will be explained in detail with reference toexamples and drawings. However, the present disclosure is not limited tothe following embodiments, examples, and drawings.

In a first aspect of the present disclosure, there is provided a methodfor forming a silicon-containing thin film, including: bringing a gasincluding a chlorosilane compound represented by the chemical formula ofSi_(n)Cl_(2n+2) (wherein, n is an integer of from about 3 to about 10)and a reactant gas including an element selected from the groupconsisting of nitrogen, oxygen, carbon, and their combinations intocontact with a substrate including at least one trench having an aspectratio of about 1 or more and a width of about 1 μm or less.

The aspect ratio may be, for example, about 1 or more, about 5 or more,about 10 or more, about 15 or more, or about 20 or more, and the widthmay be, for example, about 1 μm or less, about 0.5 μm or less, or about0.1 μm or less, but may not be limited thereto.

In accordance with an example embodiment of the present disclosure, thethin film may be formed by, but not limited to, a chemical vapordeposition (CVD) method or an atomic layer deposition (ALD) method.

In accordance with an example embodiment of the present disclosure, athickness of the silicon-containing thin film may be about 100 nm orless, but may not be limited thereto.

In accordance with an example embodiment of the present disclosure, athickness of the silicon-containing thin film may be about 30 nm orless, but may not be limited thereto.

In accordance with an example embodiment of the present disclosure, thesubstrate may be maintained at a temperature of from room temperature toabout 800° C. or less, but may not be limited thereto.

In accordance with an example embodiment of the present disclosure, thesubstrate may be maintained at a temperature of from room temperature toabout 560° C. or less, but may not be limited thereto.

In accordance with an example embodiment of the present disclosure, thesubstrate may be maintained at a temperature of from room temperature toabout 520° C. or less, but may not be limited thereto.

In accordance with an example embodiment of the present disclosure, thesubstrate may be maintained at a temperature of from about 190° C. toabout 560° C., but may not be limited thereto.

In accordance with an example embodiment of the present disclosure, thesubstrate may be maintained at a temperature of from about 280° C. toabout 520° C., but may not be limited thereto.

In accordance with an example embodiment of the present disclosure, thesubstrate may be maintained at a temperature of from about 300° C. toabout 450° C., but may not be limited thereto.

In accordance with an example embodiment of the present disclosure, thereactant gas including an element selected from the group consisting ofnitrogen, oxygen, carbon, and their combinations may not be specificallylimited as long as it can react with the chlorosilane compound. By wayof example, the reactant gas containing nitrogen may include an ammonia(NH₃)-containing gas or an alkylamine-containing gas, but may not belimited thereto. In the alkylamine-containing gas, the alkylamine mayinclude an amine including an alkyl group having about 1 to about 10carbon atoms, an amine including an alkyl group having about 1 to about8 carbon atoms, an amine including an alkyl group having about 1 toabout 6 carbon atoms, or an amine including an alkyl group having about1 to about 4 carbon atoms, and the alkyl group may be a linear orbranched alkyl group, but may not be limited thereto. By way of example,the alkylamine may include a gas selected from the group consisting ofmethylamine, ethylamine, isopropylamine, t-butylamine, and isomersthereof, but may not be limited thereto.

By way of example, the reactant gas containing oxygen may include amember selected from the group consisting of an oxygen (O₂)-containinggas, an ozone (O₃)-containing gas, a water (H₂O) vapor-containing gas,and their combinations, but may not be limited thereto.

By way of example, the reactant gas containing carbon may include analkylamine-containing gas, but may not be limited thereto. In thealkylamine-containing gas, the alkylamine may include an amine includingan alkyl group having about 1 to about 10 carbon atoms, an amineincluding an alkyl group having about 1 to about 8 carbon atoms, anamine including an alkyl group having about 1 to about 6 carbon atoms,or an amine including an alkyl group having about 1 to about 4 carbonatoms, and the alkyl group may be a linear or branched alkyl group, butmay not be limited thereto. By way of example, the alkylamine mayinclude a gas selected from the group consisting of methylamine,ethylamine, isopropylamine, t-butylamine, and isomers thereof, but maynot be limited thereto.

In accordance with an example embodiment of the present disclosure, themethod for forming a silicon-containing thin film may includealternately bringing the gas containing the chlorosilane compound andthe reactant gas including an element selected from the group consistingof nitrogen, oxygen, carbon, and their combinations into contact withthe substrate, but may not be limited thereto.

In accordance with an example embodiment of the present disclosure, thechlorosilane compound may include a member selected from the groupconsisting of Si₃Cl₈, Si₄Cl₁₀, and Si₅Cl₁₂, but may not be limitedthereto.

In accordance with an example embodiment of the present disclosure, thesilicon-containing thin film may include a silicon oxide thin film, asilicon nitride thin film, or a silicon carbonitride thin film, but maynot be limited thereto.

In accordance with an example embodiment of the present disclosure, thereactant gas may include ammonia, but may not be limited thereto. If agas containing the ammonia is used as the reactant gas, a siliconnitride thin film may be formed. If a gas containing the alkylamine isused as the reactant gas, a silicon carbonitride thin film may beformed.

In accordance with an example embodiment of the present disclosure, thechlorosilane compound represented by the chemical formula ofSi_(n)Cl_(2n+2) (wherein, n is an integer of from about 3 to about 10)may include a linear or branched isomer thereof, but may not be limitedthereto.

In accordance with an example embodiment of the present disclosure,various silicon-containing thin films such as a silicon oxide thin film,a silicon nitride thin film, or a silicon carbonitride thin film may beformed as a uniform thickness using the chlorosilane compound includinga member selected from the group consisting of Si₃Cl₈, Si₄Cl₁₀, andSi₅Cl₁₂ as a precursor by the CVD method or the ALD method, but may notbe limited thereto.

In an example embodiment of the present disclosure, a thickness of thesilicon-containing thin film may be about 100 nm or less, about 80 nm orless, about 50 nm or less, about 30 nm or less, about 10 nm or less,about 5 nm or less, or about 1 nm or less, but may not be limitedthereto. In an example embodiment of the present disclosure, thethickness of the silicon nitride thin film may be about 100 nm or less,about 80 nm or less, about 50 nm or less, about 30 nm or less, about 10nm or less, about 5 nm or less, or about 1 nm or less, but may not belimited thereto.

In accordance with an example embodiment of the present disclosure,there is provided a method for forming a silicon nitride thin film,including: bringing a gas containing the chlorosilane compoundrepresented by the chemical formula of Si_(n)Cl_(2n+2) (wherein, n is aninteger of from about 3 to about 10) and a gas containing ammonia intocontact with a substrate. The silicon nitride thin film may be formed bya chemical vapor deposition method in which the gas containing thechlorosilane compound and the gas containing ammonia are brought intocontact with the substrate at the same time or by an atomic layerdeposition method in which the gas containing the chlorosilane compoundand the gas containing ammonia are alternately brought into contact withthe substrate, but may not be limited thereto. By way of example, thechlorosilane compound may include a member selected from the groupconsisting of Si₃Cl₈, Si₄Cl₁₀, and Si₅Cl₁₂, but may not be limitedthereto.

In accordance with an example embodiment of the present disclosure,there is provided a method for forming a silicon oxide thin film,including: bringing a gas containing the chlorosilane compoundrepresented by the chemical formula of Si_(n)Cl_(2n+2) (wherein, n is aninteger of from about 3 to about 10) and a gas containing oxygen intocontact with a substrate. The silicon oxide thin film may be formed by achemical vapor deposition method in which the gas containing thechlorosilane compound and the gas containing oxygen are brought intocontact with the substrate at the same time or by an atomic layerdeposition method in which the gas containing the chlorosilane compoundand the gas containing oxygen are alternately brought into contact withthe substrate, but may not be limited thereto. By way of example, thechlorosilane compound may include a member selected from the groupconsisting of Si₃Cl₈, Si₄Cl₁₀, and Si₅Cl₁₂, but may not be limitedthereto.

In accordance with an example embodiment of the present disclosure,there is provided a method for forming a silicon carbonitride thin film,including: bringing a gas containing the chlorosilane compoundrepresented by the chemical formula of Si_(n)Cl_(2n+2) (wherein, n is aninteger of from about 3 to about 10) into contact with a substrate and agas containing nitrogen and carbon. As the gas containing nitrogen andcarbon, a gas containing an alkylamine may be used. The siliconcarbonitride thin film may be formed by a chemical vapor depositionmethod or an atomic layer deposition method, but may not be limitedthereto. By way of example, the chlorosilane compound may include amember selected from the group consisting of Si₃Cl₃, Si₄Cl₁₀, andSi₃Cl₁₂, but may not be limited thereto.

If it is necessary to form a film having a uniform thickness on asurface of a substrate including a protrusion or recess, particularly atrench having a small width and a high aspect ratio, the atomic layerdeposition method is more desirable. When the atomic layer depositionmethod is used, there may be used a conventional time-division atomiclayer deposition apparatus configured to supply each source gas insequence. Further, there may be used a space-division atomic layerdeposition apparatus configured to allow a substrate to repeatedly movein and out of a first space filled with a gas containing thechlorosilane compound and a second space filled with an additionalreactant gas in sequence.

In manufacturing a semiconductor device, for example, when a siliconnitride thin film is formed, a gas containing ammonia (NH₃) as anitrogen source may be mainly used as the additional reactant gas.Nitrogen gas (N₂) cannot be used since it has a too low reactivity, andhydrazine (N₂H₄) is not suitable to be used in a semiconductor processsince it has the risk of explosion. Ammonia gas has a high reactivity ata high temperature but has a low reactivity at a temperature of about550° C. or less, and thus, it is difficult to form a silicon nitridethin film having excellent properties using ammonia gas as a nitrogensource at a temperature of about 550° C. or less. In a case that anitrogen source, such as hydrazine, having a higher reactivity thanammonia gas cannot be used in a semiconductor process due to the risk ofexplosion, a new method capable of forming a silicon nitride thin filmhaving excellent properties using ammonia is needed. If ammonia has alow reactivity at a low temperature of about 550° C. or less, it ispossible to form a silicon nitride thin film having excellent propertiesusing a silicon source having a higher reactivity at this temperaturerange.

When the chlorosilane compound represented by the chemical formula ofSi_(n)Cl_(2n+2) (wherein, n is an integer of from about 3 to about 10)is pyrolyzed, SiCl₂ or SiCl gas having a high reactivity may begenerated. It has been theoretically suggested that when a Si₃Cl₈ gas isused as a source, SiC can be formed at a much lower temperature, ascompared with a case where SiCl₄ gas is used [V. G. Sevast'yanov, Yu. S.Ezhov, R. G. Pavelko, and N. T. Kuznetsov, “Perchlorosilanes andPerchlorocarbosilanes as Precursors for SiC Synthesis”, InorganicMaterials, 2007, Vol. 43, No. 4, pp. 369-372]. In this article, it waspredicted by a computational chemical method that Si₃Cl₈ gas ispyrolyzed at a low temperature at which SiCl₄ gas is not pyrolyzed sothat SiCl₂ gas and SiCl₃ gas are generated, which suggests that SiC canbe generated at a low temperature. Since silicon atom having four bondshas the highest stability, SiCl₃ is more reactive than SiCl₄, SiCl₂ ismore reactive than SiCl₃, SiCl is more reactive than SiCl₂, and Si ismore reactive than SiCl. Upon anticipating that a Si—Si bond is brokenon a surface of a substrate or in a gas state at a high temperature,when n is about 3 or more, about 4 or more, or about 5 or more in thechlrorosilane compound represented by Si_(n)Cl_(2n+2), it can beanticipated that highly reactive SiCl₂, SiCl, and Si are generated, asshown by the following scheme:

[Scheme]

Cl₃Si—SiCl₃→2SiCl₃;

Cl₃Si—SiCl₂—SiCl₃→2SiCl₃+SiCl₂;

Cl₃Si—SiCl₂—SiCl₂—SiCl₃→2SiCl₃+2SiCl₂;

Cl₃Si—SiCl(SiCl₃)—SiCl₃→3SiCl₃+SiCl;

Cl₃Si—SiCl₂—SiCl₂—SiCl₂—SiCl₃→2SiCl₃+3SiCl₂;

Cl₃Si—SiCl(SiCl₃)—SiCl₂—SiCl₃→3SiCl₃+SiCl₂+SiCl;

Cl₃Si—Si(SiCl₃)₂—SiCl₃→4SiCl₃+Si.

In accordance with an example embodiment of the present disclosure, thesubstrate may be maintained at a temperature of from room temperature toabout 800° C. or less, but may not be limited thereto. By way ofexample, if a gas containing the chlorosilane compound represented bySi_(n)Cl_(2n+2) (wherein, n is about 3, or an integer of from about 3 toabout 10) is used, a temperature of the substrate may not be speciallylimited.

In accordance with the present disclosure, it is possible to form ahigh-quality silicon-containing thin film using the chlorosilanecompound represented by the chemical formula Si_(n)Cl_(2n+2) (wherein, nis about 3, or an integer of from about 3 to about 10) at a lowtemperature of about 560° C. or less, about 520° C. or less, about 450°C. or less, or less than about 450° C.

In accordance with an example embodiment of the present disclosure, thesubstrate may be maintained at a temperature of from room temperature toabout 560° C. or less, or from room temperature to about 520° C. orless, or from about 190° C. or more to about 560° C. or less, or fromabout 280° C. or more to about 520° C. or less, or from about 300° C. toabout 450° C. or less, but may not be limited thereto.

In an example embodiment of the present disclosure, the substrate may bemaintained at a temperature of from room temperature to about 560° C. orless, or from room temperature to about 520° C. or less, or from about190° C. to about 560° C. or less, or about 450° C. or less or less thanabout 450° C., or from about 300° C. or more to about 450° C. or less orless than about 450° C., for example, from about 150° C. to about 520°C., from about 280° C. to about 520° C., from about 300° C. to about520° C., from about 320° C. to about 520° C., from about 350° C. toabout 520° C., from about 370° C. to about 520° C., from about 400° C.to about 520° C., from about 420° C. to about 520° C., from about 150°C. to about 450° C., from about 170° C. to about 450° C., from about200° C. to about 450° C., from about 220° C. to about 450° C., fromabout 250° C. to about 450° C., from about 270° C. to about 450° C.,from about 300° C. to about 450° C., from about 320° C. to about 450°C., from about 350° C. to about 450° C., from about 370° C. to about450° C., from about 400° C. to about 450° C., from about 150° C. toabout 440° C., from about 170° C. to about 440° C., from about 200° C.to about 440° C., from about 220° C. to about 440° C., from about 250°C. to about 440° C., from about 270° C. to about 440° C., from about300° C. to about 440° C., from about 320° C. to about 440° C., fromabout 350° C. to about 440° C., from about 370° C. to about 440° C., orfrom about 400° C. to about 440° C., but may not be limited thereto.

In an example embodiment of the present disclosure, the chlorosilanecompound may include a member selected from the group consisting ofSi₃Cl₈, Si₄Cl₁₀, and Si₅Cl₁₂, but may not be limited thereto. Achlorosilane compound having a too large molecular weight cannot beapplied to a chemical vapor deposition method or an atomic layerdeposition method due to a low vapor pressure thereof. Therefore, thechlorosilane compound in accordance with the present disclosure mayinclude chlorosilane compounds represented by the chemical formula ofSi_(n)Cl_(2n+2) where n is an integer of about 10 or less among thechlorosilane compounds represented by the chemical formulaSi_(n)Cl_(2n+2) where n is about 3 or more. By way of example, thechlorosilane compound may be a chlorosilane compound in which the aboven is an integer of about 3 to about 5, but may not be limited thereto.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present disclosure will be explained in detail withreference to examples. However, the present disclosure is not limitedthereto.

EXAMPLE Example 1 Formation of Silicon Nitride Thin Film by Atomic LayerDeposition Using OCT (Si₃Cl₈) Gas and Ammonia Gas

Octachlorotrisilane (OCT, Si₃Cl₈) was put into a container heated to 65°C., and the OCT gas vaporized from the container and ammonia gas werealternately brought into contact with a silicon substrate placed in anatomic layer deposition chamber. When the OCT gas heated to 65° C. wassupplied without a separate carrier gas, an internal pressure of thechamber was maintained at 0.5 Torr, and when only the ammonia gas wassupplied, an internal pressure of the chamber was maintained at 9.5Torr. The silicon substrate was constantly maintained at a temperaturein a range of from 150° C. to 600° C. An atomic layer deposition cycleincluding OCT gas supply→evacuation→Ar gas supply for 40seconds→evacuation→ammonia gas supply→evacuation→Ar gas supply for 40seconds→evacuation was repeated 40 times, to form a silicon nitride thinfilm. A thickness and a characteristic of the silicon nitride thin filmwere analyzed. If a carrier gas is used in the atomic layer depositioncycle, a mixed gas of the OCT gas and the carrier gas may be usedinstead of the OCT gas. For another reason, a mixed gas of the OCT gasand an inert gas may be used. A mixed gas of ammonia gas and an inertgas may be used instead of the ammonia gas.

FIG. 1A and FIG. 1B are graphs each showing film growth according to anatomic layer deposition method in which a silicon substrate ismaintained at 520° C. in accordance with the present example and anexposure amount of octachlorotrisilane (OCT) gas and an exposure amountof ammonia gas independently varies in one cycle of an atomic layerdeposition. Herein, an exposure amount unit L corresponds to 1 langmuir(=1×10⁻⁶ Torr×1 second). Therefore, an OCT exposure amount of 6×10⁷ Lmeans that the substrate is exposed to the OCT gas under a pressure of0.5 Torr for 120 seconds. Further, an ammonia exposure amount of 2×10⁸ Lmeans that the substrate is exposed to the ammonia gas under a pressureof 9.5 Torr for 22 seconds. It can be seen that even if the OCT exposureamount is increased to be 6×10⁷ L or more or the ammonia exposure amountis increased to be 2×10⁸ L or more when the substrate has a temperatureof 520° C., film growth does not increase, and, thus, an atomic layerdeposition is possible at 520° C.

An atomic layer deposition experiment was carried out using OCT gassupplied for 120 seconds and ammonia gas supplied for 110 seconds atvarious temperatures of the substrate. Film growth depending on atemperature of the substrate was as shown in FIG. 2. FIG. 2 is a graphshowing film growth of silicon nitride thin films respectively formed atvarious temperatures of the substrate in accordance with the presentexample. In a substrate temperature range of from 282° C. to 520° C., afilm having a uniform thickness could be obtained from each atomic layerdeposition cycle regardless of exposure amounts of the OCT gas and theammonia gas.

A silicon nitride thin film was formed by repeating the atomic layerdeposition cycle 20 times using the OCT and ammonia gases at 520° C. ona silicon wafer surface including a trench having a width of 40 nm, anda depth of 2 μm with an aspect ratio of 50:1 under the above-describedcondition, and the silicon nitride thin film was observed with atransmission electron microscope (TEM). It was confirmed that thesilicon nitride thin film was measured to have a thickness of 4.62 nm atthe inlet of the trench and 4.36 nm at the bottom of the trench so thata step coverage was 94% (=4.36/4.62) which is very close to a desiredvalue of 100%.

Thicknesses and refractive indexes of silicon nitride thin filmsrespectively formed at various temperatures of a substrate using OCT andammonia gases were measured right after the film formation, 1 day, 3days and 6 days after the film formation and shown in FIG. 3A and FIG.3B. FIG. 3A and FIG. 3B are graphs showing results of the measurementconducted right after film formation, 1 day later, 3 days later, and 6days later after the film formation on thicknesses and refractiveindexes of silicon nitride thin films respectively formed at varioustemperatures of a substrate in accordance with the present example ofthe present disclosure. A thickness of the silicon nitride thin filmformed at 282° C. or less was increased as time passed, but a thicknessof the silicon nitride thin film formed at 372° C. or more was rarelychanged as time passed. The silicon nitride thin film formed at a hightemperature of the substrate had a refractive index closer to arefractive index 2.0 of silicon nitride. A refractive index of thesilicon nitride thin film formed at 282° C. or less was decreased astime passed. A composition of the silicon nitride thin film formed at282° C. or less was not close to a stable composition of Si₃N₄, and,thus, the silicon nitride thin film reacted with moisture or oxygen (O₂)gas in air to be converted into silicon oxynitride. Therefore, it can beconstrued that the refractive index is changed to be close to arefractive index 1.45 of silicon oxide (SiO₂).

From this result, it can be seen that the substrate temperature in arange of from 300° C. to 520° C. is desirable in forming a siliconnitride thin film having a stable composition using OCT as a siliconsource.

Example 2 Formation of Silicon Nitride Thin Film by Atomic LayerDeposition Using DCT (Si₄Cl₁₀) Gas and Ammonia Gas

Dodecachlorotetrasilane (DCT, Si₄Cl₁₀) was put into a container heatedto 80° C., and a DCT gas vaporized from the container and ammonia gaswere alternately brought into contact with a silicon substrate placed inan atomic layer deposition chamber. When the DCT gas heated to 80° C.was supplied without a separate carrier gas, an internal pressure of thechamber was maintained at 0.1 Torr, and when only ammonia gas wassupplied, an internal pressure of the chamber was maintained at 9.5Torr. The silicon substrate was constantly maintained at a temperaturein a range of from 190° C. to 560° C. An atomic layer deposition cycleincluding a DCT gas supply for 100 seconds→evacuation→Ar gas supply for40 seconds→evacuation→ammonia gas supply for 110 seconds→evacuation→Argas supply for 40 seconds→evacuation was repeated 40 times, to form asilicon nitride thin film. A thickness of the silicon nitride thin filmwas analyzed. If a carrier gas is used in the atomic layer depositioncycle, a mixed gas of the DCT gas and the carrier gas may be usedinstead of the DCT gas. For another reason, a mixed gas of the DCT gasand an inert gas may be used. A mixed gas of ammonia gas and an inertgas may be used instead of the ammonia gas.

An atomic layer deposition experiment was carried out using DCT gas andammonia gas at various temperatures of the substrate. Film growthdepending on a temperature of the substrate was as shown in FIG. 2. FIG.2 shows film growth of silicon nitride thin films respectively formed atvarious temperatures of the substrate in accordance with the presentexample. In the substrate temperature range of from 190° C. to 560° C.,a film having a uniform thickness was obtained from each atomic layerdeposition cycle regardless of exposure amounts of the DCT gas and theammonia gas.

Comparative Example 1 Formation of Silicon Nitride Thin Film by AtomicLayer Deposition Using Hexachlorodisilane (HCD, Si₂Cl₆) Gas orDichlorosilane (DCS, SiH₂Cl₂) Gas and Ammonia Gas

A silicon nitride thin film was formed under the same condition as inExample 1 except that HCD or DCS was used instead of OCT. An atomiclayer deposition experiment was carried out at various temperatures ofthe substrate. Film growth depending on a temperature of the substratewas as shown in FIG. 2. Unlike Example 1 and Example 2 in which a filmhaving a uniform thickness was obtained from each atomic layerdeposition cycle regardless of exposure amounts of the OCT or DCT gasand the ammonia gas, there was no temperature range in which a filmhaving a uniform thickness could be obtained from each atomic layerdeposition cycle using the HCD or DCS gas. This means that an ALDprocess cannot be performed using the HCD or DCS gas and the ammoniagas. If the ALD process cannot be performed, a silicon nitride thin filmhaving a uniform thickness cannot be formed on a pattern having a highaspect ratio of a substrate surface including a trench having a smallwidth and a high aspect ratio.

From Example 1, Example 2, and Comparative Example 1, it can be seenthat in order to achieve the purpose of forming a silicon nitride thinfilm with a uniform thickness on a substrate including a protrusion orrecess, particularly a substrate including a trench having a small widthand a high aspect ratio, at a temperature of 560° C. or less, the atomiclayer deposition method using the chlorosilane compound-containing gasand the ammonia gas in accordance with the present disclosure is muchmore desirable as compared with the atomic layer deposition method usingthe HCD or DCS gas and ammonia gas.

A silicon nitride thin film can be formed to a thickness of about 8 nmat a temperature of from room temperature to about 560° C. or from about300° C. to about 560° C. by an atomic layer deposition method.Therefore, it is possible to form a silicon nitride thin film with auniform thickness of 100 nm or less, 30 nm or less, or 10 nm or less ona substrate including a protrusion or recess such as at least one trenchhaving an aspect ratio of 1 or more and a width of 1 μm or less.

Example 3 Formation of Silicon Oxide Thin Film by Atomic LayerDeposition Using Si₄Cl₁₀ Gas

Si₄Cl₁₀ was stored in a container. The container was hated at 90° C.,and N₂ was used as a carrier gas at a flow late of 50 sccm. A pressureof the container was controlled at 50 Torr. O₃ was used as an oxygensupply source. A silicon substrate was heated at 350° C. During a firststep, Si₄Cl₁₀ was introduced into a reaction chamber for 2 seconds.Then, as a second step, N₂ purging was carried out for 5 seconds. Then,as a third step, O₃ purging was applied to the reaction chamber for 2seconds, and as a fourth step, N₂ purging was carried out for 2 seconds.SiO₂ thin film was obtained by an atomic layer deposition method ofrepeating the above four steps 100 times.

Example 4 Formation of Silicon Oxide Thin Film by Chemical VaporDeposition Using Si₄Cl₁₀ Gas

Si₄Cl₁₀ was stored in a container. The container was hated at 90° C.,and N₂ was used as a carrier gas at a flow late of 50 sccm. A pressureof the container was controlled at 50 Torr. Si₄Cl₁₀ was mixed with amixture of O₂/N₂ gases in a reaction chamber. A silicon substrate washeated at 500° C. An internal pressure of the reaction chamber was setto 100 Torr. SiO₂ thin film was obtained by such a process.

The above description of the present disclosure is provided for thepurpose of illustration, and it would be understood by those skilled inthe art that various changes and modifications may be made withoutchanging technical conception and essential features of the presentdisclosure. Thus, it is clear that the above-described embodiments areillustrative in all aspects and do not limit the present disclosure. Forexample, each component described to be of a single type can beimplemented in a distributed manner. Likewise, components described tobe distributed can be implemented in a combined manner.

The scope of the present disclosure is defined by the following claimsrather than by the detailed description of the embodiment. It shall beunderstood that all modifications and embodiments conceived from themeaning and scope of the claims and their equivalents are included inthe scope of the present disclosure.

We claim:
 1. A method to form a silicon-containing thin film,comprising: supplying a gas including a chlorosilane compoundrepresented by the chemical formula of Si_(n)Cl_(2n+2) (wherein n is aninteger of from 4 to 10) and a reactant gas including an elementselected from the group consisting of nitrogen, oxygen, carbon, andtheir combinations to a substrate including at least one fine trenchhaving an aspect ratio of 1 or more and a width of 1 μm or less to formthe silicon-containing thin film having a uniform film thickness on asurface of the substrate including a surface of the fine trench, andwherein the silicon-containing thin film is formed by an atomic layerdeposition (ALD) method, and wherein a thickness of thesilicon-containing thin film is about 80 nm or less, and wherein atemperature of the substrate is in a range of temperature at which theALD using the gas including the chlorosilane compound is carried out. 2.The method to form a silicon-containing thin film of claim 1, whereinthe thickness of the silicon-containing thin film is about 30 nm orless.
 3. The method to form a silicon-containing thin film of claim 1,wherein the substrate is maintained at a temperature of from an ambienttemperature to about 800° C.
 4. The method to form a silicon-containingthin film of claim 1, wherein the substrate is maintained at atemperature of from an ambient temperature to about 560° C.
 5. Themethod to form a silicon-containing thin film of claim 1, wherein thesubstrate is maintained at a temperature of from about 280° C. to about520° C.
 6. The method to form a silicon-containing thin film of claim 1,wherein the substrate is maintained at a temperature of from about 300°C. to about 450° C.
 7. The method to form a silicon-containing thin filmof claim 1, wherein the reactant gas includes a member selected from thegroup consisting of an ammonia (NH₃)-containing gas, analkylamine-containing gas, an oxygen (O₂)-containing gas, an ozone(O₃)-containing gas, a water (H₂O) vapor-containing gas, and theircombinations.
 8. The method to form a silicon-containing thin film ofclaim 1, wherein the gas including chlorosilane compound and thereactant gas are alternately supplied to the substrate.
 9. The method toform a silicon-containing thin film of claim 1, wherein thesilicon-containing thin film includes a silicon oxide thin film, asilicon nitride thin film, or a silicon carbonitride thin film.
 10. Themethod to form a silicon-containing thin film of claim 1, wherein thechlorosilane compound includes a member selected from the groupconsisting of Si₄Cl₁₀, and Si₅Cl₁₂.
 11. The method to form asilicon-containing thin film of claim 10, wherein the reactant gasincludes ammonia, and the silicon-containing thin film includes asilicon nitride thin film.
 12. A method to form a silicon-containingthin film, comprising: supplying a gas including a chlorosilane compoundrepresented by the chemical formula of Si₃Cl₈ and a reactant gasincluding to a substrate including at least one fine trench having anaspect ratio of 1 or more and a width of 1 μm or less to form thesilicon-containing thin film having a uniform film thickness on asurface of the substrate including a surface of the fine trench, andwherein the silicon-containing thin film is formed by an atomic layerdeposition (ALD) method, and wherein a thickness of thesilicon-containing thin film is about 80 nm or less, and wherein atemperature of the substrate is maintained at a temperature from about300° C. to about 520° C.
 13. The method of claim 12, wherein thetemperature of the substrate is maintained at a temperature from about300° C. to about 440° C.
 14. The method of claim 12, wherein thereactant gas includes ammonia (NH₃).